JP2007157638A - Light source device and image display device using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source device which is improved in utilization efficiency of emitted light from a plurality of point light sources and small in size and light in weight, and an image display device using the same. <P>SOLUTION: The light source device 10 comprises point light sources 1-3, a photosynthetic prism part 4, and an integrator part 5. The photosynthetic prism part 4 has a plurality of light incident faces 4a, 4c, 4d, a plurality of dichroic faces S1, S2, and a light outgoing face 4b, and the integrator part 5 has a light guide path constituted of a plurality of reflecting surfaces 5c to 5f, a light incident port made of one end face of the light guide path, and a light outgoing port made of the other end face 5b. The point light sources 1 to 3 are arranged adhered tightly to the light incident faces 4a, 4c, 4d of the photosynthetic prism part 4, and the photosynthetic prism part 4 and the integrator part 5 are integrated so that the light outgoing face 4b and the light incident port 5a may face each other. The image display device is provided with the light source device, a light modulation means, and a projection optical system. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image display device, and more particularly to a light source device including a plurality of point light sources and a projection-type image display device using the light source device.

  Conventionally, discharge lamps such as ultra-high pressure mercury lamps, metal halide lamps, and xenon lamps have been used as light sources for projection image display devices (hereinafter also referred to as projectors) such as front projectors and rear projection televisions. On the other hand, in recent years, projectors using red (R), green (G), and blue (B) light emitting diodes (LEDs) as light sources have been developed, which contributes to the reduction in size and weight of projectors and is free from color reproducibility. Performance exceeding the electric light system has been reported (for example, see Patent Document 1). In addition, the LED light source does not use mercury compared to the discharge lamp light source, has excellent explosion-proof properties, and can be driven by a battery using a relatively simple drive circuit. As such, it has various excellent features.

  FIG. 10 is a perspective view showing an optical system of a conventional projector using an LED light source. An optical system 100 shown in FIG. 10 includes a light source module 102, a convex lens 103, an integrator rod 104, a relay lens system 105, an image display element 106, and a projection lens 101. The light source module 102 includes a red LED, a blue LED, and a green LED. It is comprised from several LED121 containing LED and the condensing lens 122 corresponding to each LED121, respectively. The convex lens 103 is disposed on the entrance port 104a side of the integrator rod 104, and the relay lens system 105 including the first relay lens 151 and the second relay lens 152 is disposed on the exit port 104b side of the integrator rod 104. Yes.

  The optical system 100 is intended to improve color rendering properties and light utilization efficiency by the configuration as described above, and the way light travels in the optical system 100 is as follows. The light emitted from each LED 121 is guided to the convex lens 103 while being condensed by the corresponding condenser lens 122. Then, the light focused by the convex lens 103 enters the integrator rod 104 from the incident port 104a, and is emitted as a uniform light beam from the output port 104b. Light emitted from the integrator rod 104 is guided to the image display element 106 by the relay lens system 105, and reflected light from the surface is projected on the screen by the projection lens 101.

Japanese Unexamined Patent Publication No. 2004-126203 ([0024] to [0034], FIG. 1)

  However, in the optical system 100 shown in FIG. 10, the LED 121 is disposed at a distance of about the focal length from the condenser lens 122 and is coupled to the integrator rod 104 via the condenser lens 122 and the convex lens 103. Therefore, there is a possibility that a coupling loss due to leaked light may occur. In particular, when an LED having a large spread angle of emitted light is used, there is a problem that the coupling loss increases and the light amount of the projector is reduced. . Similarly, the light emitted from the integrator rod 104 is guided to the image display element 106 via the relay lens system 105 including the first relay lens 151 and the second relay lens 152, and thus coupling by leakage light is performed. Loss can occur.

  Furthermore, since the optical system 100 requires lens groups 122, 103, 151, and 152 that are configured separately from the integrator rod 104, an increase in the number of parts increases the cost of the projector and decreases the reliability. In addition, there is a problem that the optical system 100 becomes large and has low volume utilization efficiency.

  In addition, in order to improve the light collection efficiency of the light emitted from the LED 121, if a light collection lens 122 having a large aperture diameter is used, the number of light collection lenses 122, and thus, It becomes difficult to increase the number of corresponding LEDs 121, and it becomes difficult to increase the amount of light of the projector by increasing the number of LEDs.

  The present invention has been made in view of the above problems, and has a function of combining light emitted from a plurality of point light sources and a light equalizing function, and improves the utilization efficiency of light emitted from the point light sources. Another object of the present invention is to provide a small and lightweight light source device and an image display device using the light source device.

In order to achieve the above object, a light source device according to the present invention is a light source device including a plurality of point light sources, a light combining prism unit, and an integrator unit, wherein the light combining prism unit includes a plurality of light incident units. The integrator unit comprising: a surface; a plurality of dichroic surfaces that selectively reflect or transmit light incident on the inside from the light incident surface; and a light emitting surface that emits light reflected or transmitted through the dichroic surface. Is provided with a light guide path constituted by a plurality of reflecting surfaces, a light incident port consisting of one end face of the light guide path, and a light exit opening consisting of the other end face of the light guide path,
Each of the plurality of point light sources is disposed in close contact with one of the light incident surfaces of the light combining prism unit, and the light emitting surface of the light combining prism unit and the light incident port of the integrator unit are substantially the same. The light combining prism portion and the integrator portion are integrated so that the light emitting surface of the light combining prism portion and the light entrance of the integrator portion face each other.

  According to the present invention, a plurality of point light sources are disposed in close contact with any of the light incident surfaces of the light combining prism unit, and the light emitting surface of the light combining prism unit and the light incident port of the integrator unit have substantially the same shape. By combining the light combining prism unit and the integrator unit so that the light emitting surface of the light combining prism unit and the light incident port of the integrator unit face each other, each of the light source, the combining prism unit, and the integrator unit The components can be coupled with high efficiency without using a separate lens group. As a result, it is possible to capture light emitted from a plurality of point light sources with extremely small coupling loss, improve the volume utilization efficiency of the light source device, reduce the number of parts, and achieve a compact and highly reliable light source. An apparatus can be provided.

  In one aspect of the present invention, the light combining prism portion is formed in a substantially cubic shape having one side surface as the light emitting surface and five side surfaces other than the light emitting surface as the light incident surface. Four dichroic surfaces are provided that selectively reflect or transmit light incident from the four light incident surfaces that are substantially orthogonal to each other, and transmit light incident from the light incident surface facing the light exit surface. It is what.

  By setting the optical configuration prism unit to the above-described predetermined configuration, it is possible to synthesize light emitted from a maximum of five point-like light sources by a single light synthesis prism unit without requiring optical axis adjustment. As a result, it is possible to easily and inexpensively configure a light source device having a high-luminance multi-lamp configuration while maintaining high volume utilization efficiency. Further, light having various spectral distributions can be synthesized by appropriately combining point light sources that emit light of various wavelengths.

  In addition, the light source device according to the present invention preferably includes a Fresnel lens provided at one or both of the light incident port and the light emitting port of the integrator unit. It is possible to arbitrarily control the spread angle of the emitted light and guide the light to any subsequent optical element such as a light modulation unit with high efficiency.

  In one embodiment of the present invention, the integrator unit is a solid translucent member, and has a refractive index distribution in a direction perpendicular to the optical axis of the integrator unit. Thus, the spread angle of the light emitted from the integrator unit is arbitrarily controlled.

  Furthermore, the light source device according to the present invention may be configured by arranging a plurality of the light source devices having a predetermined configuration in parallel. Since the light source device according to the present invention has a relatively simple configuration in which the combining prism unit and the integrator unit are integrated, the optical axis adjustment and the like can be performed by arranging a plurality of light source devices in one unit in parallel. The light source device having a high luminance and multiple lighting configuration can be easily and inexpensively maintained while maintaining high volume utilization efficiency.

  An image display device according to the present invention includes the light source device according to the present invention, a light modulation unit that spatially modulates light from the light source device based on image information, and light from the light modulation unit. And a projection optical system for projecting in an enlarged manner.

  According to the image display device of the present invention, the light source device is greatly reduced in size and weight, so that the reduction in size and weight of the image display device is promoted. Since the light emitted from the light source can be captured without coupling loss and the number of point light sources can be easily increased, the brightness of the image display device can be increased easily and inexpensively. In addition, since the light emission brightness of the light source device can be easily adjusted by changing the number of lamps of a plurality of point light sources, an image display having an optimal light source according to the desired brightness of the image projected on a screen or the like The device can be designed.

  Since the present invention is configured as described above, it has a function of combining and uniformizing light emitted from a plurality of point light sources, and is small and lightweight with improved utilization efficiency of light emitted from the point light sources. A light source device can be provided. In addition, by using the light source device, it is possible to promote the reduction in size, weight, and increase in brightness of the projection type image display device. For example, it is suitable as a simple projector for mobile use that supports battery driving. A simple image display device can be easily realized.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings. However, the drawings are for explanation, and do not necessarily accurately reflect actual shapes and dimensions.

(First embodiment)
FIG. 1 is a perspective view showing a main part of a light source device 10 according to a first embodiment of the present invention. As shown in FIG. 1, the light source device 10 includes a plurality of point light sources 1, 2, and 3, a light combining prism unit 4, and an integrator unit 5.

  In the present embodiment, the point light sources 1, 2, and 3 are light emitting diodes (LEDs) that emit light having different wavelengths. For example, the point light source 1 is light having a first wavelength (for example, green). The point light source 2 emits light of a second wavelength (for example, blue), and the point light source 3 emits light of a third wavelength (for example, red).

  The light combining prism unit 4 is formed in a substantially rectangular parallelepiped shape from three optical prism units 4A, 4B, and 4C. One side surface including one side surface 4a and regions 4c and 4d is used as a light incident surface, and one side surface 4b is used as light. This is the exit surface. A dichroic surface S1 is formed on the joint surface between the optical prism units 4A and 4B, and a dichroic surface S2 is formed on the joint surface between the optical prism units 4B and 4C.

  These dichroic surfaces S1 and S2 are formed by a dielectric multilayer film so as to have predetermined wavelength selective reflection / transmission characteristics. In the present embodiment, the dichroic surface S2 reflects the light of the third wavelength from the point light source 3 and transmits the light of the first and second wavelengths, and the dichroic surface S1 The light having the second wavelength from the light source 2 is reflected and the light having the first wavelength is transmitted.

  Further, in this embodiment, the integrator unit 5 has a light guide path in which the four side surfaces 5c, 5d, 5e, and 5f are formed as light reflecting surfaces, the one end surface 5a is a light incident port, and the other end surface 5b is a light emitting port. It constitutes. At that time, the integrator unit 5 may be formed as a solid quadrangular prism from glass or a translucent material such as transparent resin such as acrylic resin or polycarbonate resin, or the side surface 5c. It may be formed as a hollow quadrangular prism by combining light reflecting wall surfaces corresponding to 5d, 5e, and 5f.

  In the light source device 10 according to the present embodiment, the light emitting surface 4b of the light combining prism unit 4 and the light incident port 5a of the integrator unit 5 have substantially the same shape, and the light combining prism unit 4 and the integrator unit 4 are configured to perform light combining. The light exit surface 4b of the prism part 4 and the light incident port 5a of the integrator part 5 are integrated by means such as adhesion, for example. The point light source 1 is on the light incident surface 4 a of the light combining prism unit 4, the point light source 2 is on the light incident surface 4 c of the light combining prism unit 4, and the point light source 3 is on the light incident surface 4 d of the light combining prism unit 4. They are arranged in close contact with each other.

  In the light source device 10 configured as described above, the light emitted from each of the point light sources 1, 2, and 3 is synthesized from the light incident surfaces 4 a, 4 c, and 4 d that are in close contact with each other without causing coupling loss. The light enters the portion 4 and is reflected or transmitted by the dichroic surfaces S1 and S2 described above, and the combined light thereof is guided to the light emitting surface 4b. Next, the combined light emitted from the light emitting surface 4b of the combining prism unit 4 enters the integrator unit 5 from the light incident port 5a integrated with the combining prism unit 4 without causing coupling loss. The light flux uniformized by the multiple reflection at the light reflecting surfaces 5c, 5d, 5e, and 5f is emitted from the light exit port 5b.

  As described above, the light source device 10 according to the present embodiment has high efficiency without using separate lens groups for the constituent elements of the plurality of point light sources 1, 2 and 3, the combining prism unit 4, and the integrator unit 5. Thus, it is possible to incorporate light emitted from a plurality of point light sources 1, 2, and 3 with extremely small coupling loss, and to provide a small and highly reliable light source device It is.

  In the present embodiment, the combining prism unit 4 is formed by joining a single two-wave dichroic prism having a dichroic surface S1 and a single two-wave dichroic prism having a dichroic surface S2 in series. It may be.

  Further, as in the optical device 20 shown in FIG. 2, the combining prism unit in the present embodiment is configured in a substantially cubic shape from the four optical prism units 4A, 4B, 4C, and 4D, and the dichroic surface S1 (second Reflects light of wavelength and transmits light of first and third wavelengths and dichroic surface S2 (reflects light of third wavelength and transmits light of first and second wavelengths) And so-called cross cube prism 14 formed so as to intersect with each other.

Hereinafter, other embodiments of the present invention will be described, but in the following description, descriptions of portions common to the respective embodiments will be omitted as appropriate, and characteristic portions of each embodiment will be described in detail.

(Second Embodiment)
FIG. 3 is a perspective view showing a main part of the light source device 30 according to the second embodiment of the present invention. The light source device 30 in the present embodiment uses the light combining prism unit 24 as a five-wave combining dichroic prism, and one light combining prism unit 24 emits light from five point light sources 1, 2, 3, 34, and 35. Is different from the light source devices 10 and 20 in the first embodiment described above in that the configuration is combined. Hereinafter, with reference to FIG. 4, the configuration of the light combining prism unit 24 which is a main feature of the present embodiment will be described.

  FIG. 4 is a diagram showing a configuration of a dichroic prism (hereinafter also referred to as a double cross cube prism) 24 used for the light source device 30 for synthesizing five waves, where (a) is an assembled state, (b) and (c). These are perspective views respectively shown in an exploded state.

  As shown in FIG. 4A, the double cross cube prism 24 has one side surface 24b as a light exit surface and five side surfaces 24a, 24c, 24d, 24e, and 24f other than the light exit surface 24b as light incident surfaces. Light is incident on each of the four light incident surfaces 24c, 24d, 24e, and 24f substantially orthogonal to the light exit surface 24b and is selectively reflected or transmitted through the light exit surface 24b. Are provided with four dichroic surfaces S1, S2, S3, and S4 that transmit light incident from the light incident surface 24a.

  That is, in the double cross cube prism 24, the dichroic surface S1 reflects the second wavelength light from the point light source 2 incident from the light incident surface 24c, and transmits the other wavelength light. It has transmission characteristics. Similarly, the dichroic surface S2 reflects the third wavelength from the point light source 3 incident from the light incident surface 24e and transmits light of other wavelengths, and the dichroic surface S3 enters from the light incident surface 24d. The fourth wavelength light from the point light source 34 is reflected and the other wavelength light is transmitted, and the dichroic surface S4 receives the fifth wavelength light from the point light source 35 incident from the light incident surface 24f. Each has wavelength selective reflection / transmission characteristics of reflecting and transmitting light of other wavelengths. Moreover, all the dichroic surfaces S1-S4 transmit the light of the 1st wavelength from the point light source 1 which injects from the light-incidence surface 24a.

  In the present embodiment, the wavelengths of the first to fifth lights described above may be all different or may include light in the same wavelength band, and the luminance required for the light source device 30. For example, the first wavelength is green light, the second wavelength is blue light, the third wavelength is red light, and the fourth wavelength is yellow-green. The fifth wavelength can be cyan. In this configuration, the total amount of green light can be increased by combining yellow-green and cyan, and a bright light source device with excellent color rendering can be obtained.

  Here, an example of a specific configuration of the double cross cube prism 24 is as follows. First, as shown in FIG. 4B, the double cross cube prism 24 is decomposed into four triangular prism-shaped blocks A, A, B, and B whose height direction is in the Z direction (see FIG. 4A). Then, the block A is composed of four optical prism units, ie, a pair of optical prism units a1 and a1 and another pair of optical prism units a2 and a2, and the block B is optically coupled with a pair of optical prism units b2 and b2. It consists of a prism unit b1. At this time, the dichroic surfaces S1 and S2 that intersect in the XY plane and extend in the Z direction are formed on the surfaces constituting the side surfaces of the blocks A and B of the optical prism units a1, a2, b1, and b2. Has been.

  On the other hand, as shown in FIG. 4C, the double cross cube prism 24 is decomposed into four triangular prism-shaped blocks C, C, D, and D whose height direction is in the Y direction (see FIG. 4A). Then, the block C is composed of four optical prism units, ie, a pair of optical prism units a1 and a1, and another pair of optical prism units b2 and b2, and the block D is optically coupled with the pair of optical prism units a2 and a2. It consists of a prism unit b1. At this time, the dichroic surfaces S3 and S4 that intersect in the XZ plane and extend in the Y direction are formed on the surfaces constituting the side surfaces of the blocks C and D of the optical prism units a1, a2, b1, and b2, respectively. Has been.

  In the light source device 30 in the present embodiment, the light combining prism portion 24 is a double cross cube prism, so that in addition to the same functions and effects as those of the first embodiment described above, a maximum of five point light sources 1 are used. 2, 3, 34, and 35 can be combined by a single light combining prism unit 24 without the need for optical axis adjustment. Can be configured easily and inexpensively while maintaining high volume utilization efficiency. In addition, by appropriately combining the wavelengths of the emitted light from the point light sources 1, 2, 3, 34, and 35 used, light having various spectral distributions can be easily realized as the synthesized light emitted from the synthesis prism unit 24. can do.

  Here, for the light source devices 10, 20, and 30 shown in FIGS. 1 to 3, the integrator unit 5 has a substantially rectangular parallelepiped shape. However, the integrator unit in the light source device according to the present invention includes the light source device 40 shown in FIG. Like the integrator unit 15, it may be formed in a tapered shape that tapers from the light incident port 15 a toward the light emitting port 15 b. Since the integrator 15 has such a configuration, the number of times of total reflection of light propagating in the integrator 15 is increased, so that the uniforming action can be increased.

  Although FIG. 5 is shown as having the light combining prism portion 4 shown in FIG. 1, a similar integrator portion 15 can be used together with the light combining prism portions 14 and 24 shown in FIGS. . Similarly, in the following description, when a configuration corresponding to the light source device in the specific embodiment described above (for example, the light source device 10 illustrated in FIG. 1) is shown for convenience of description, It goes without saying that the embodiment (for example, the light source devices 20, 30, and 40 shown in FIGS. 2, 3, and 5) can be replaced.

(Third embodiment)
FIGS. 6A and 6B are perspective views showing a third embodiment of the light source device according to the present invention. The light source device 50 shown in FIG. 6A includes a Fresnel lens 26 disposed in the light exit port 5b of the integrator unit 5 in addition to the same configuration as the light source device 10 shown in FIG. , And are integrated with the light exit port 5b of the integrator unit 5 by means such as adhesion.

  Here, the Fresnel lens 26 reproduces the curved surface of one lens surface (for example, a convex lens) by a set of a plurality of minute refractive surfaces provided concentrically on one surface of a flat light-transmitting substrate. Thus, the spread angle of the emitted light from the integrator unit 5 can be arbitrarily controlled. Since the light source device according to the present invention can easily integrate the flat Fresnel lens 26 like the light source device 50 shown in FIG. 6A, the light source device retains the characteristics as a small light source device with a small number of parts. As it is, the emitted light from the integrator unit 5 can be efficiently guided to the subsequent optical element (for example, a light modulation unit to be described later).

  Further, in the light source device according to the present invention, the Fresnel lens 26 may be disposed in the light incident port 5a of the integrator unit 5 as in the light source device 60 shown in FIG. In this case, the light combining prism unit 4 and the integrator unit 5 are integrated via the Fresnel lens 26. In the light source devices 50 and 60 shown in FIGS. 6A and 6B, the Fresnel lens 26 is formed separately from the integrator unit 5. However, the integrator unit 5 is made of a translucent member. When configured as a solid prism, a Fresnel lens may be integrally formed on the end face forming the light exit port 5b or the light entrance port 5a.

  Furthermore, through the above-described embodiments, when the integrator unit is made of a solid translucent member, it can have a refractive index distribution in a direction perpendicular to the optical axis of the integrator unit. Next, a configuration example of the integrator unit 25 having a refractive index distribution will be described with reference to FIG.

  FIG. 7A is a perspective view schematically showing the configuration of the integrator unit 25, and FIG. 7B is a cross section (YZ cross section) perpendicular to the optical axis L of the integrator unit 25 shown in FIG. ) Is a diagram schematically showing.

  The integrator section 25 is formed by laminating a plurality of rectangular parallelepiped-shaped translucent resins. FIG. 7A shows a total of 64 rectangular parallelepipeds, 8 layers in the Y direction and 8 layers in the Z direction. An example in which the integrator unit 25 is configured by stacking layers is shown. The integrator unit 25 has one end 25 a as a light incident port and the other end 25 b as a light output port. Each rectangular parallelepiped constituting the integrator unit 25 is one in the optical axis L direction (X direction) of the integrator unit 25. It has various refractive indexes. Hereinafter, the rectangular parallelepipeds constituting the integrator unit 25 are referred to with the coordinates (1, 1) to (8, 8) as shown in FIG.

  As shown in FIG. 7 (b), in the integrator 25, the rectangular parallelepipeds (4, 5), (5, 5), (4, 4), (5, 4) is composed of a member having the highest refractive index, and its peripheral portion (the hatching portion that is lowered to the right) including the rectangular parallelepiped (3, 7) is composed of a member having a lower refractive index than the central portion. Further, the outermost edge portion (the portion without hatching) including the rectangular parallelepiped (1, 1) and the like is formed of a member having the lowest refractive index.

  With the configuration as described above, the light incident from the light incident port 25a of the integrator unit 25 is converged as it propagates through the integrator 25 and is emitted from the light output port 25b.

  The refractive index distribution as described above is shown as an example, and an integrator unit having an arbitrary desired refractive index distribution is designed by appropriately changing the refractive index configuration of each rectangular parallelepiped constituting the integrator unit 25. be able to. Thereby, similarly to the Fresnel lens 26 shown in FIG. 6, the spread angle of the light emitted from the integrator unit 25 can be arbitrarily controlled.

(Fourth embodiment)
Next, a fourth embodiment of the light source device according to the present invention will be described with reference to FIG. The light source device according to the present invention may be configured by arranging the light source devices in the first to third embodiments described above as one unit and arranging them in parallel. FIG. 8A is a perspective view showing a light source device 70 in which the light source devices 10 shown in FIG. 1 are arranged in parallel by two units, and FIG. 8B is similarly a light source device 10 shown in FIG. It is a perspective view which shows the light source device 80 formed by arranging 4 units in parallel.

  Since the light source device 10 is formed by combining a plurality of point light sources 1, 2, 3, the light combining prism unit 4, and the integrator unit 5 without using a separate lens group or the like, A plurality of light source device units 10-1, 10-2, 10-3, and 10-4 corresponding to the light source device 10 are arranged in parallel as in the light source devices 70 and 80 shown in 8 (a) and (b). Therefore, it can be easily combined without requiring adjustment of the optical axis. As a result, it is possible to easily and inexpensively configure a light source device having a high-intensity multi-light configuration while maintaining the feature of the light source device according to the present invention that is high volume utilization efficiency.

  As shown in FIGS. 8A and 8B, when using a Fresnel lens in the light source devices 70 and 80, each light source device unit 10-1, 10-2, 10-3, 10-4. Fresnel lenses 27 and 29 having lens surfaces with respect to and Fresnel lenses 28 and 31 having one lens surface corresponding to the spread of light emitted from the Fresnel lenses 27 and 29 are used in series. Is preferred. In that case, more preferably, at least the Fresnel lenses 27 and 29 are configured integrally with the light source device units 10-1, 10-2, 10-3, and 10-4.

(Fifth embodiment)
Next, an image display apparatus using the light source device according to the present invention will be described as a fifth embodiment of the present invention. In the embodiment described below, the light source device includes the light source device 50 shown in FIG. 6, but it goes without saying that any of the other light source devices described above may be included.

  FIG. 9 is a diagram showing a main part of the optical system of the image display device 90 according to the fifth embodiment of the present invention. As shown in FIG. 9, the image display device 90 expands the light from the light source device 50, the light modulation unit 54 that spatially modulates the light from the light source device 50 based on the image information, and the light from the light modulation unit 54. Projection optical system 56 for projecting.

  In the present embodiment, the light modulation means 56 is, for example, a transmissive liquid crystal display element that controls transmission / non-transmission of light in units of pixels in accordance with image information from a driving device (not shown). This liquid crystal display element may be provided with a color filter, and each pixel may be composed of red, green, and blue color pixels, or separate from a liquid crystal display element such as a dichroic mirror (not shown). Body color separation means may be provided. Further, the light modulation means 56 may be a reflection type light modulation means such as a DMD element, and may be provided with a color separation means such as a color wheel (not shown).

  According to the image display device of the present invention, the light source device 50 is greatly reduced in size and weight, and the optical system can be configured without using a separate lens group. A reduction in size and weight of the display device 50 is promoted. Further, the light source device 50 takes in light emitted from a plurality of point light sources without coupling loss, and the number of light points of the point light sources can be easily increased. The brightness of the apparatus can be increased easily and inexpensively.

It is a perspective view which shows the light source device in the 1st Embodiment of this invention. It is a perspective view which shows another structural example of the light source device in the 1st Embodiment of this invention. It is a perspective view which shows the light source device in the 2nd Embodiment of this invention. It is a figure which shows the structure of the light synthesis prism part used with the light source device shown in FIG. 3, (a) is a perspective view in an assembly state, (b), (c) is a perspective view in an exploded state, respectively. It is a perspective view which shows another structure of the integrator part which concerns on this invention. It is a perspective view which shows the light source device in the 3rd Embodiment of this invention, (a) is the structural example which arrange | positions a Fresnel lens in the light-projection opening of an integrator part, (b) is a light incident port of an integrator part. It is the example of a structure arrange | positioned. It is a figure which shows the structure of the integrator part which has the refractive index distribution which concerns on this invention, (a) is a perspective view which shows the structure typically, (b) is a cross section perpendicular | vertical to the optical axis of an integrator part typically FIG. It is a figure which shows the light source device in the 4th Embodiment of this invention, (a) is a perspective view which shows the light source device of 2 unit structure, (b) is a perspective view which shows the light source device of 4 unit structure. It is a figure which shows the principal part of the optical system in the image display apparatus in the 5th Embodiment of this invention. It is a perspective view which shows the structure of the optical system of the conventional image display apparatus.

Explanation of symbols

1, 2, 3, 34, 35: point light source, 4, 14, 24: light combining prism unit, 4a, 4c, 4c, 24a, 24c, 24d, 24e, 24f: light incident surface, 4b, 24b: light emission 5, 15, 25: integrator unit, 5 a, 15 a, 25 a: light entrance, 5 b, 15 b, 25 b: light exit, 54: light modulation means, 56: projection optical system, 90: image display device

Claims (6)

A light source device including a plurality of point light sources, a light combining prism unit, and an integrator unit,
The light combining prism unit emits a plurality of light incident surfaces, a plurality of dichroic surfaces that selectively reflect or transmit light incident on the light incident surfaces from the inside, and light reflected or transmitted by the dichroic surfaces. The integrator unit includes a light guide path configured by a plurality of reflection surfaces, a light incident port formed from one end surface of the light guide path, and a light output port formed from the other end surface of the light guide path. With
Each of the plurality of point light sources is disposed in close contact with the light incident surface of any of the light combining prism portions,
The light emitting surface of the light combining prism unit and the light incident port of the integrator unit have substantially the same shape, and the light combining prism unit and the integrator unit include the light emitting surface of the light combining prism unit and the integrator unit. The light source device is integrated so as to face the light incident port.   The light combining prism portion is formed in a substantially cubic shape having one side surface as the light emitting surface and five side surfaces other than the light emitting surface as the light incident surface, and the four light beams substantially orthogonal to the light emitting surface. Four dichroic surfaces are provided that selectively reflect or transmit light incident from each incident surface and transmit light incident from the light incident surface facing the light exit surface. The light source device according to claim 1.   The light source device according to claim 1, further comprising a Fresnel lens provided at one or both of the light incident port and the light emitting port of the integrator unit.   The light source according to claim 1, wherein the integrator unit is a solid translucent member and has a refractive index distribution in a direction perpendicular to the optical axis of the integrator unit. apparatus.   A light source device comprising a plurality of light source devices according to claim 1 arranged in parallel. 6. The light source device according to claim 1, a light modulating unit that spatially modulates light from the light source device based on image information, and expanding light from the light modulating unit. An image display device comprising a projection optical system for projecting.

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